Vehicles are being developed that have reduced weight and improved fuel economy. Turbochargers are being incorporated into engine designs to compensate for reductions in engine displacement as part of the effort to improve fuel economy. Lower displacement engines provided with turbochargers run at higher revolutions per minute (RPMs) and generate more noise than engines having similar torque output. The exhaust side of turbochargers generate high heat particularly after the engine is turned off and air circulation is minimized.
Cowl structures are used to attenuate noise from the engine. Cowl structures include extension dash panels (EDPs) that are removable to facilitate engine servicing. Prior art EDPs may be manufactured from stamped steel or aluminum or may be made of sheet molding compounds (SMCs). EDPs made of stamped metal or SMC add weight and increase the cost of the parts and cost of labor for installation. Layers of sound absorbing insulation may be needed to reduce the transmission of engine noise into the passenger compartment of the vehicle. The layers of sound absorbing material are attached with fasteners that also add weight and increase part cost and assembly labor.
EDPs are subjected to high heat in the engine compartment and may be installed near the turbocharger exhaust area. EDPs made of common thermoplastic material may melt or be distorted when exposed to the high temperatures in the engine compartment of a vehicle near a turbocharger. Heat shields may be required to protect the EDP from the heat generated by the turbocharger exhaust. The heat shields may include foam layers between the EDP and the heat shields to absorb and deflect heat.
This disclosure is directed to solving the above problems and other problems as summarized below.